Rotary harrows

ABSTRACT

A rotary harrow has soil-working members that are protected and, to some extent, supported from the ground by an elongated transverse beam that is pivoted to the front of the frame. The beam is spring biased to an operative location adjacent the soil-working member connections and vertically adjustable with respect to those members. The beam is rounded off at its lower surfaces to level the ground and ride along the ground. If debris becomes lodged between the beam and soil-working members, the beam can pivot forwardly against spring opposition to release the debris. The pivot axis for the beam is substantially directly above the beam itself.

This invention relates to a rotary harrow comprising a transverse framewith coupling means at the front of such frame for attaching the harrowto a prime mover. A plurality of soil working members rotatable mountedon upwardly extending shafts supported on said transverse frame portionand drive means connected to said shaft to rotate said soil workingmembers.

According to the invention a rotary harrow of the kind set forth isprovided with a soil leveling member in front of the said soil workingmembers which soil leveling member extends throughout substantially thewhole of the working width of said harrow and at least partly supportsthe harrow during operation.

For a better understanding of the invention and to show how the same maybe carried into effect, reference will now be made, by way of example,to the accompanying drawings, in which:

FIG. 1 is a plan view of a rotary harrow in accordance with theinvention,

FIG. 2 is a side elevation, to an enlarged scale, as seen in thedirection indicated by an arrow II in FIG. 1,

FIG. 3 is a section, to an enlarged scale, taken on the line III--III ofFIG. 1,

FIG. 4 is an underneath view of one part of the harrow as seen in thedirection indicated by an arrow IV in FIG. 3,

FIG. 5 is a section taken on the line V--V of FIG. 3.

Referring to FIGS. 1 to 5 of the drawings, the rotary harrow or soilcultivator which is illustrated has a frame portion 1 of hollow box-likeconfiguration that exten-ds substantially horizontally perpendicular tothe intended direction of operative travel of the harrow which isindicated by an arrow A in FIG. 1. The frame portion 1 accommodates aplurality (in this case, 12) of vertical or substantially verticalrotary shafts 2 that are regularly spaced apart from one another in asingle row by centre-to-centre distances of substantially 25centimeters. The lowermost end of each shaft 2 carries a correspondingsoil-working member or rotor that is generally indicated by thereference 3. Each shaft 2 is rotatably supported at the bottom of theframe portion 1 by a bearing and also by a further bearing at the top ofsaid portion 1, the uppermost bearings being secured to a substantiallyhorizontal top plate 4 of the frame portion 1 which top plate 4 isitself secured to the rims of an underlying dished plate of said frameportion by small bolts. Each shaft 2 is provided inside the hollow frameportion 1 with a corresponding spur-toothed pinion 5 and it will be seenin broken lines in FIG. 1 of the drawings that the teeth of each pinion5 are in driven or driving and driven mesh with those of its neighbouror each of its two neighbours. The lowermost end of each rotary shaft 2projects from the bottom of the frame portion 1 and is there providedwith a substantially horizontally extending strong wrought iron flange 6and each flange 6 has a horizontal portion 9 of a corresponding one ofthe soil working members or rotors 3 secured to it by two substantiallyvertical bolts 7 that are formed from a strong but relatively easilyfractured material. The horizontal portion 9 of each soil working memberor rotor 3 has its opposite ends connected to two upright blades 8 whichblades, in this embodiment, are integral with the opposite ends of theportion 9, said blades 8 and portion 9 conveniently being made fromsingle pieces of sheet metal. Each blade 8 preferably has a length ofsubstantially 12 centimeters between its upper and lower extremities.

It can be seen from FIG. 4 of the drawings that the blades 8 of eachsoil working member or rotor 3 are turned or twisted to some extentabout their own longitudinal axes and that their leading edges withrespect to the intended directions of rotation of the correspondingshafts 2 are formed as rearwardly and downwardly inclined cutting edges10 that extend throughout substantially two-thirds of the upright lengthof each blade 8. It will also be noted that, due to the aforementionedturning or twisting of the blades 8, the cutting edges 10 thereof arecloser to the axes of rotation afforded by the corresponding shafts 2than are the rearmost plain edges of the blades 8.

Upright brackets 11 are provided on top of the frame portion 1 and atthe front thereof with respect to the direction A, said brackets 11having arms 12 pivotally connected to them with the aid of substantiallyhorizontal pins 14. The arms 12 extend downwardly and forwardly in pairsand their lowermost ends are interconnected by a substantiallyhorizontal soil leveling member afforded by a beam 13 of light-weightconstruction that extends throughout substantially the whole of theworking width of the harrow. It will be seen from FIGS. 2 and 3 of thedrawings that the lower surface and front of the beam 13 with respect tothe direction A is effectively rounded-off and that, in cross-section,said beam is generally inclined downwardly and rearwardly with respectto the direction A from its top. The pins 14 that afford pivotalconnections between the brackets 11 and the arms 12 are entered throughsingle aligned holes in the upper ends of the arms 12 but through anyselected one of a number of vertically spaced holes 15 in eachrespective bracket 11. The pins 14 are located in substantial verticalalignment with the beam 13 and the front of frame portion 1, as seen inthe drawings. Resilient "safety" pins 16A are passed through transversebores near the ends of the pins 14 to retain those pins in theirselected positions and it will be realised that the particular holes 15which are selected for co-operation with the pins 14 determine theheight of the beam 13 relative to the frame portion 1 thus governing toa large extent the depth of penetration of the blades 8 into the soilduring operation of the harrow. A helical tension spring 16 is stretchedbetween horizontally aligned holes in each pair of arms 12 and acorresponding adjusting screw 17, said holes in the arms 12 being formedat a level below that of the pivot pins 14. The longitudinal axes of thetwo springs 16 both extend substantially horizontally and the twoadjusting screws 17 are entered through holes in supporting brackets 18mounted at the top and rear of the frame portion 1, the shanks of thescrews 17 being provided with pairs of nuts which can be displacedaxially of the screws to increase or decrease the initial degree oftension of the springs 16 as may be required.

The shaft 2 of one of the central pair of soil working members or rotors3 is provided with an upward extension 19 that is entered axiallythrough a tube 21 that is fastened on top of the frame portion 1 bysupports 20. The extension 19 has its upper end rotatably journalled ina gear box 22 and is provided inside that gear box with a bevel pinion23. The bevel pinion 23 is in driven mesh with a smaller bevel pinion 24located at the inner end of a forwardly projecting substantiallyhorizontal rotary input shaft 25. It will be noted that the top of thegear box 22 is afforded by a removable plate 25A that is inclineddownwardly and rearwardly from its leading edge to its rear edge withrespect to the direction A.

Substantially vertical supports 26 located at the opposite lateral sidesor ends of the frame portion 1 carry a funnel-shaped container or hopper27 of a mechanism 28 for supplying materials such as seeds, fertilisers,pesticides and the like onto and/or into the soil, said hopper 27 beingelongated in a substantially horizontal direction that is perpendicularto the direction A. The hopper 27 accommodates a feed mechanism 27A(FIG. 3) that is located above the upper ends of tubular deliverymembers 29 that extend from the base of the hopper 27 downwardly andrearwardly with respect to the direction A towards the rear of theharrow. The lowermost end of each tubular delivery member 29 is providedwith an upwardly and downwardly displaceable portion 29A (FIGS. 3 and 5)the portions 29A being upwardly and downwardly displaceable relative toa support 30 carried at the rear of the frame portion 1. The support 30carries a plurality of brackets 31 that are equal in number to thenumber of displaceable portions 29A and each bracket 31 houses, betweenits limbs, a corresponding slider 32 formed with a row of holes 34. Thelimbs of the brackets 31 are formed with single horizontally alignedholes and a horizontal locking pin 33 is provided for insertion throughthose holes and a chosen intervening hole 34 of the slider 32, thechosen hole 34 thus determining the setting of the correspondingdisplaceable portion 29A relative to the tubular delivery member 29under consideration. The rear of each slider 32 with respect to thedirection A is provided with a corresponding pair of tines 37 that areformed from a single length of spring steel or other resilient wire orrod. The junction between the two tines 37 of each pair takes the formof a substantially 180° bend which is fastened to the correspondingslider 32 by a clamp 36 and a bolt 35 entered between the limbs of saidbend. Each pair of tines 37 extends upwardly from the correspondingclamped bend through substantially 180° curves 38 that are orientatedrearwardly with respect to the direction A, the free ends of said bends38 merging into 360° loops 39 which loops, in turn, terminate instraight working portions 40 that are downwardly and rearwardly inclinedwith respect to the direction A at substantially the same angles as thedelivery members 29 to which they are indirectly connected.

The front of the frame portion 1 with respect to the direction A carriesa generally triangular coupling member or trestle 41 that is adapted forconnection, in a manner that is known per se, to the three-point liftingdevice or hitch of an agricultural tractor or other operating vehicle.Rearwardly and downwardly divergent tie bars 42 extend between the topof the coupling member 41 and locations at the top and rear of the frameportion 1. A strengthening strip 43 also extends between the top of thecoupling member 41 and a central location at the front of the hopper 27,said strip 43 thus extending substantially parallel to the direction A.

In the use of the rotary harrow that has been described with referenceto FIGS. 1 to 5 of the drawings, its coupling member or trestle 41 isconnected in known manner to the three-point lifting device of anagricultural tractor or other operating vehicle and the leading end ofthe splined or otherwise keyed rotary input shaft 25 is placed in drivenconnection with the power take-off shaft of the same tractor or otheroperating vehicle with the aid of an intermediate telescopictransmission shaft (not shown) of known construction having universaljoints at its opposite ends. After the beam 13 in front of the frameportion 1 has been adjusted to a desired height by entering the pins 14through appropriate holes 15, the harrow can be moved upwardly out ofoperation and downwardly into operation by appropriate control of thelifting device or hitch of the tractor or other operating vehicle. Asthe harrow is moved operatively over a field in the direction A, thesoil working members or rotors 3 are rotated from the gear box 22 insuch a way that the two rotors 3 of each neighbouring pair revolve inopposite directions, all of the rotors 3 working individual strips ofsoil which overlap one another to produce, in effect, a single broadstrip of worked soil because the distances between the blades 8 of eachrotor 3 are greater than the perpendicular distances between the axes ofrotation of neighbouring rotors 3 about their axes of rotation areangularly staggered to prevent the blades 8 from fouling one anotherduring operation. The downwardly and rearwardly bevelled cutting edges10 of the blades 8 are located foremost with respect to the direction ofrotation of each rotor 3 and it has been found that the angularlytwisted or turned positions of the blades 8 about their longitudinalaxes minimises the risk of the blades cutting out large lumps or clodswhen heavy soil is being worked so that the number of such lumps orclods which are produced is very small indeed. Owing to the structure ofthe soil working members or rotors 3 which has been described above andwhich is illustrated in FIGS. 3 and 4 of the drawings, the cutting edges10 of the blades 8 are nearer to the axes of rotation of the rotors thanare the trailing edges of said blades and this ensures that the soil isfrequently cut along its natural lines of rupture or breakage. Thedescribed and illustrated disposition of the leading cutting edges 10 ofthe blades 8 ensures that weeds, stubble and the like are readilychopped and loosened from the ground. As the rotary harrow movesforwardly over the soil that is to be worked, the soil leveling memberin form of the beam 13 rides over the surface of that soil partiallysupporting the harrow and levelling the surface of the soil due to theeffectively rounded-off leading and lower surface of the beam. If astone or other obstacle should get one or more of the rotors 3 and thebeam 13, said beam can deflect forwardly against the action of thesprings 16 thus releasing the stone or other obstacle. As previouslymentioned, the depth of penetration of the blades 8 into the soil can bevaried by raising or lowering the horizontal level of the beam 13relative to the rest of the harrow by engaging the pins 14 inappropriate holes 15. FIG. 3 of the drawings show two different possiblehorizontal settings of the beam 13 in full and broken linesrespectively. If desired, the strip of land that has been worked by theblades 8 of the rotors 3 can immediately be sown with seeds by themechanism 28. Said mechanism 28 will then function as a seed drill andall that is necessary is to move the sliders 32 downwardly to an extentthat is suitable to match the operating level set by the position of thebeam 13 and subsequently to replace the pins 33 in appropriate holes 34.The adjustment of the displaceable portions 29A which resultssimultaneously adjusts the positions of the tines 37 which tines serveto agitate the soil that has been formed into furrows by the precedingportions 29A, which serve as coulters under these circumstances, thusleaving a substantially smooth sown seedbed in which a very largemajority of the seeds will be at the correct depth and covered with alayer of fine soil. The feed mechanism 27A may be driven from one end ofthe hopper 27 by an assembly that is not shown in the drawings but whichcomprises a ground-engaging wheel, roller or the like that is rotated bytravel of the harrow over the ground in the direction A, such rotationbeing mechanically transmitted to the feed mechanism 27A. Alternatively,the mechanism 27A may be rotated by drive derived from the operatingtractor or other vehicle through the intermediary of the rotary inputshaft 25.

In the rotary harrow which has been described, the blades 8 of each ofthe soil working members or rotors 3 are preferably made from singlepieces of sheet material which includes the intermediate horizontalportion 9. The horizontal portions 9 are fastened to the flanges 6 bythe breakable bolts 7 and this construction has the advantage ofavoiding damage to the soil working members or rotors 3 if they shouldmeet a substantially immovable obstacle during the operation of theharrow since, upon a predetermined resistance to rotation beingexceeded, the bolts 7 will shear thus freeing the corresponding flange 6and shaft 2. It is only necessary to replace the broken bolts 7 torestore the harrow to its fully operative condition. The rotary harrowthat has been described above in which the blades 8 have effectivelengths of substantially 12 centimeters each is particularly suitablefor the rapid preparation of soil for the sowing of cereal crops, therelatively simple construction of the harrow allowing to be manufacturedat a competitive price even though it includes a seed drill which enablethe cereal crops to be sown simultaneously with the preparation of theseed bed.

What is claimed is:
 1. A rotary harrow comprising a frame with couplingmeans at the front thereof for attaching the harrow to a prime mover, anelongated portion of said frame extending transverse to the direction oftravel and a plurality of soil-working members rotatably mounted onupwardly extending shafts supported on said transverse frame portion,drive means connected to said shafts and said soil-working members beingrotatable by said drive means, an elongated ground engaging member beingpositioned in front of said soil-working member and extending forsubstantially the entire working width of said harrow, said groundengaging member being pivoted to said frame and deflectable againstresilient opposition in a forward direction, said member being pivotableabout an axis that extends substantially horizontally and perpendicularto the direction of travel, said axis being located substantially invertical alignment with said ground engaging member.
 2. A harrow asclaimed in claim 1, wherein said ground engaging member is pivotallyconnected to spaced apart bracket means at the front of said frameportion with respect to the direction of travel, members beingvertically adjustable with respect to said bracket means and means forfixing that member in any one of a plurality of positions.
 3. A harrowas claimed in claim 1, wherein said ground engaging member has a lowersurface that is rounded off with respect to the direction of travel,said member being normally positioned at a level adjacent saidsoil-working members and partly supporting said harrow during operation.4. A harrow as claimed in claim 1, wherein said ground engaging memberis a hollow beam having a cross-section generally inclined downwardlyand rearwardly from the top thereof, with respect to the direction oftravel.
 5. A harrow as claimed in claim 2, wherein said bracket meansincludes spaced apart brackets that extend substantially verticallyupwardly from connections to the front of the frame portion and saidbeam has arms pivoted to the brackets by pins, said pins being locateddirectly above the front of said frame portion.